The Effect of Swimming Activity and Section of the Vagus Nerves on Heart Rate in Rainbow Trout

1974 ◽  
Vol 60 (2) ◽  
pp. 305-319 ◽  
Author(s):  
IMANTS G. PRIEDE
Keyword(s):  
Heart Rate ◽  
Maximum Rate ◽  
Critical Speed ◽  
Swimming Activity ◽  
Vagus Nerves ◽  
Maximum Heart Rate ◽  
Heart Rates ◽  
Cardiac Responses ◽  
Different Temperatures ◽  
Speed Up

1. Heart rates associated with swimming activity were measured in intact and vagotomized fish at 6.5 and 15 °C. 2. Low swimming speeds had no effect on heart rate but above a threshold speed it increased logarithmically with swimming speed up to the critical speed and maximum heart rate. 3. Times for recovery after exercise increased rapidly above the critical speed. 4. Bilaterally vagotomized fish at 6.5 °C showed high resting heart rates and erratic cardiac responses to exercise. 5. In bilaterally vagotomized fish at 15 °C heart rates were normal except for a low maximum rate. 6. It is concluded that the vagus nerve can function differently at different temperatures.

scholarly journals Stretching single titin molecules from failing human hearts reveals titin’s role in blunting cardiac kinetic reserve

2019 ◽  
Vol 116 (1) ◽  
pp. 127-137
Author(s):  
Mei-Pian Chen ◽  
Salome A Kiduko ◽  
Nancy S Saad ◽  
Benjamin D Canan ◽  
Ahmet Kilic ◽  
...  
Keyword(s):  
Heart Rate ◽  
Single Molecule ◽  
Left Ventricular ◽  
Passive Tension ◽  
Frequency Dependent ◽  
Heart Rates ◽  
Human Cardiomyocytes ◽  
Sarcomeric Protein ◽  
Novel Approach ◽  
Speed Up

Abstract Aims Heart failure (HF) patients commonly experience symptoms primarily during elevated heart rates, as a result of physical activities or stress. A main determinant of diastolic passive tension, the elastic sarcomeric protein titin, has been shown to be associated with HF, with unresolved involvement regarding its role at different heart rates. To determine whether titin is playing a role in the heart rate (frequency-) dependent acceleration of relaxation (FDAR). W, we studied the FDAR responses in live human left ventricular cardiomyocytes and the corresponding titin-based passive tension (TPT) from failing and non-failing human hearts. Methods and results Using atomic force, we developed a novel single-molecule force spectroscopy approach to detect TPT based on the frequency-modulated cardiac cycle. Mean TPT reduced upon an increased heart rate in non-failing human hearts, while this reduction was significantly blunted in failing human hearts. These mechanical changes in the titin distal Ig domain significantly correlated with the frequency-dependent relaxation kinetics of human cardiomyocytes obtained from the corresponding hearts. Furthermore, the data suggested that the higher the TPT, the faster the cardiomyocytes relaxed, but the lower the potential of myocytes to speed up relaxation at a higher heart rate. Such poorer FDAR response was also associated with a lesser reduction or a bigger increase in TPT upon elevated heart rate. Conclusions Our study established a novel approach in detecting dynamic heart rate relevant tension changes physiologically on native titin domains. Using this approach, the data suggested that the regulation of kinetic reserve in cardiac relaxation and its pathological changes were associated with the intensity and dynamic changes of passive tension by titin.

P4423Extreme bradycardia in athletes is due to intrinsic changes within the heart

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M D Flannery ◽  
F Sully ◽  
K Janssens ◽  
G Morris ◽  
J Kalman ◽  
...  
Keyword(s):  
Heart Rate ◽  
Vagal Tone ◽  
Endurance Athletes ◽  
Valsalva Manoeuvre ◽  
Resting Heart Rate ◽  
Maximum Heart Rate ◽  
Vo2 Max ◽  
Heart Rates ◽  
Intrinsic Heart Rate ◽  
Autonomic Blockade

Abstract Background It is well known that athletes and in particular endurance athletes have lower resting heart rates than non-athletes. This has generally been considered a healthy adaptation. Traditionally this was thought be due to increased vagal tone. Several studies have shown that endurance athletes continue to have lower heart rates in the absence of autonomic influence suggesting bradycardia is due to intrinsic changes within the heart. A subset of endurance athletes have very low heart rates with Tour de France cyclists having described heart rates in the 30s. It is unclear whether in these elite athletes with very low heart rates the profound bradycardia is due to autonomic influence or intrinsic changes within the heart. Aim The aim of this study was to determine if extreme bradycardia in athletes is due to excess vagal tone or more profound intrinsic changes within the heart. Methods We recruited three cohorts for this study: non-athlete controls (NA), endurance athletes with a documented resting heart rate >40 (EA) and endurance athletes with a resting heart rate <40 (BA). All participants underwent baseline testing including ECG, echocardiography and VO2 max testing. All participants came back on a second occasion for treatment with dual autonomic blockade (DAB) to determine intrinsic heart rate in the following manner. After resting supine for five minutes resting heart rate was measured. Participants were then administered 0.04mg/kg of intravenous atropine. After five minutes participants were then administered 0.05mg/kg of intravenous metoprolol. This was repeated every five minutes until there was no further drop in heart rate or 0.2mg/kg had been administered. The resting heart rate at this stage was recorded as the intrinsic heart rate. Parasympathetic blockade was confirmed by lack of response to Valsalva manoeuvre and sympathetic blockade was confirmed by lack of response to metoprolol. VO2 max testing was then performed to determine maximum heart rate. Results 9 NA (7 male), 10 EA (8 male) and 5 BA (4 male) participated in this study. The average age was similar in all groups (NA 32.9y, EA 32.4y, BA 31.4y). The average resting heart rate was 71.7 in the NA group, 48.3 in the EA group and 41.6 in the BA group (p<0.05 for comparisons between all three groups). Following dual autonomic blockade resting heart rate was 86.0 in the NA group, 76.9 in the EA group and 64.4 in the BA group (p<0.05 for comparisons between all three groups). Maximum heart rate under DAB was 140.1 in the NA group, 138.0 in the EA group and 140.4 in the BA group. These differences were not significant. Conclusion In athletes with very low heart rates, bradycardia is due to more profound intrinsic changes within the heart. Acknowledgement/Funding NHMRC Project Grant

scholarly journals The effects of acute oxygen changes on heart rate in the freshwater crab Poppiana dentata (Randall, 1840)

2020 ◽  
Vol 48 (3) ◽  
pp. 480-487
Author(s):  
Delezia Shivani Singh ◽  
Mary Alkins-Koo ◽  
Luke Victor Rostant ◽  
Azad Mohammed
Keyword(s):  
Heart Rate ◽  
Invasive Technique ◽  
Cardiac Physiology ◽  
Low Oxygen ◽  
Heart Rates ◽  
Oxygen Levels ◽  
Non Invasive ◽  
Hypoxic Conditions ◽  
Cardiac Responses ◽  
Insight Into

Heart rate is a key physiological feature that can be used to assess the response of organisms to changing environmental conditions in aquatic habitats, such as acute fluctuations in oxygen levels and hypoxic conditions. This experiment, therefore, investigated cardiac responses in a freshwater brachyuran species, Poppiana dentata, exposed to low oxygen levels. Heart rate was derived from beats per minute (bpm) signals (n = 576) using an infrared, non-invasive technique over a 96 h period, under different dissolved oxygen (DO) conditions. These involved three regimes: normoxic (6.8 ± 0.1 mg L-1), decreasing DO to hypoxic levels (6.2 to 1.7 mg L-1), and recovery with normoxic levels (6.3 ± 0.1 mg L-1). Changes in heart rates among the three regimes were significant (P < 0.05); reflecting the shift in heart rate during different conditions of oxygen availability, normoxic (59 to 61 bpm), declining DO (54 to 62 bpm) and recovery DO (53 to 64 bpm). Additionally, the normal rhythmicity of heart rates under the normoxic condition was not maintained throughout most of the declining DO and recovery periods. P. dentata has demonstrated cardiac compensations in heart rate during low oxygen levels, providing insight into the species cardiac physiology.

Renal and systemic hemodynamic responses to sustained submaximal exertion in horses

1990 ◽  
Vol 258 (5) ◽  
pp. R1177-R1183 ◽  
Author(s):  
K. W. Hinchcliff ◽  
K. H. McKeever ◽  
L. M. Schmall ◽  
C. W. Kohn ◽  
W. W. Muir
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Solid ◽  
Systemic Hemodynamics ◽  
Solid Concentration ◽  
Maximum Heart Rate ◽  
Filtration Fraction ◽  
Systemic Hemodynamic ◽  
Heart Rates

We investigated the effects of 1 h of sustained submaximal exertion on the renal and systemic hemodynamics of six horses. The horses ran on a treadmill at a speed that produced heart rates of 55-60% of each horse's maximum heart rate. Exertion produced heart rates of 121 +/- 6.6 and 126 +/- 6.1 (SE) beats/min after 15 and 60 min, respectively. Cardiac output increased significantly (P less than 0.05) from 70.1 +/- 3.1 to 246.2 +/- 4.7 ml.min-1.kg body wt-1 after 15 min of exertion and thereafter did not change. There was no significant change from rest in p-aminohippuric acid and creatinine clearances, filtration fraction, or renal blood flow during exertion. Plasma total solid concentration and hematocrit increased by 3.8 and 8.6%, respectively, between 20 and 60 min of exertion. Pulmonary artery temperature increased significantly from 37.6 degrees C at rest to 38.6 degrees C at 60 min of exertion. This study demonstrates the ability of the horse to maintain renal hemodynamics similar to resting values and systemic hemodynamics at steady-state values despite hemoconcentration and increased body temperature during sustained submaximal exertion.

Maximum heart rate responses to exercise and isoproterenol in the trained rat

1988 ◽  
Vol 254 (5) ◽  
pp. R834-R839 ◽  
Author(s):  
C. P. Bolter ◽  
K. J. Atkinson
Keyword(s):  
Heart Rate ◽  
Male Rats ◽  
Exercise Heart Rate ◽  
Maximum Heart Rate ◽  
Heart Rates ◽  
Maximum Exercise ◽  
Chronotropic Response ◽  
The Difference

Male rats were assigned to light (C) or strenuous (T) running programs. Both groups ran at 30 m/min, 8% elevation. Over 16 wk, T and C completed 2,939 +/- 72 and 507 +/- 7 min (mean +/- SE). In a graded running test, maximum exercise heart rates for T and C were 542 +/- 7 and 554 +/- 6 beats/min (P greater than 0.05). Heart rates elicited by maximum effective concentrations of isoproterenol (ISO) in vivo and in vitro were 483 +/- 8 and 489 +/- 11 beats/min for T and 499 +/- 5 and 502 +/- 5 beats/min for C (no difference between groups or treatments). A lower heart rate was recorded in T for both resting (353 +/- 7 vs. 373 +/- 4 beats/min) and in vitro intrinsic states (231 +/- 22 vs. 299 +/- 22 beats/min) (P less than 0.05 for both conditions). The difference between maximum ISO-stimulated and maximum exercise heart rates was attributed to a temperature difference. In a separate group of lightly trained rats, ISO was administered intravenously during hard exercise when heart rate approached exercise maximum. Heart rate after ISO did not increase beyond the maximum heart rate observed in a control run. It was concluded that the maximum chronotropic response to sympathetic stimulation can be elicited during hard exercise and that maximum exercise heart rate reflects this limit rather than a saturation of cardiac sympathetic activity.

scholarly journals MANFAAT LATIHAN OLAHRAGA AEROBIK TERHADAP KEBUGARAN FISIK MANUSIA

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Chrisly M. Palar ◽  
Djon Wongkar ◽  
Shane H. R. Ticoalu
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Exercise Training ◽  
Physical Fitness ◽  
Aerobic Exercise ◽  
Exercise Intensity ◽  
Aerobic Exercise Training ◽  
Maximum Heart Rate ◽  
Speed Up ◽  
The Way

Abstract: Aerobic exercise is a kind of exercise systematically by increasing the load gradually and continuously using energy derived from the combustion using oxygen, and takes oxygen without causing fatigue. Examples of aerobic exercise is the way, jogging, running, cycling, and swimming. Physical fitness is the body’s ability to function effectively when working or doing other things, and still have enough energy to handle or emergencies that may arise. Before planning to do aerobic exercise, namely: the frequency of exercise three to five times every week, exercise intensity 60 - 80% of maximum heart rate, and duration of exercise 20 – 60 minutes.mConclusion: With regular aerobic exercise, blood flow to be smooth and speed up the disposal of metabolic waste substances, so that recovery takes place rapidly, and the person with not experience fatigue after performing the task, and still be able to perform other activities. Benefits of aerobic exercise training is increased physical fitness.Keywords: aerobic exercise, physical fitness.Abstrak: Latihan olahraga aerobik ialah aktivitas olahraga secara sistematis dengan peningkatan beban secara bertahap dan terus-menerus yang menggunakan energi yang berasal dari pembakaran dengan menggunakan oksigen, dan membutuhkan oksigen tanpa menimbulkan kelelahan.Contoh latihan olahraga aerobic adalah jalan, jogging, lari, bersepeda, dan renang. Kebugaran fisik adalah kemampuan tubuh untuk berfungsi secara efektif ketika bekerja atau melakukan aktivitas lainnya, dan masih memiliki cukup energi untuk menangani atau menghadapi keadaan darurat yang mungkin timbul. Sebelum merencanakan untuk melakukan latihan olahraga aerobik, perlu memperhatikan kriteria-kriteria yang berkaitan dengan takaran latihan, yaitu: frekuensi latihan tiga sampai lima kali setiap minggu, intensitas latihan 60-80% dari denyut jantung maksimal, dan durasi latihan 20 - 60 menit. Simpulan: Dengan pembuangan zat-zat sisa metabolisme, sehingga pemulihan berlangsung dengan cepat, dan seseorang tidak akan mengalami kelelahan setelah melaksanakan tugas, serta masih dapat melakukan aktivitas lainnya. Manfaat latihan olahraga aerobik ialah kebugaran fisik meningkat.Kata kunci: Latihan olahraga aerobik, kebugaran fisik.

scholarly journals Heart Rate–Induced Myocardial Ca 2+ Retention and Left Ventricular Volume Loss in Patients With Heart Failure With Preserved Ejection Fraction

2020 ◽  
Vol 9 (17) ◽  
Author(s):  
Daniel N. Silverman ◽  
Mehdi Rambod ◽  
Daniel L. Lustgarten ◽  
Robert Lobel ◽  
Martin M. LeWinter ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Ejection Fraction ◽  
Sinus Rhythm ◽  
Left Ventricular ◽  
Atrial Pacing ◽  
Preserved Ejection Fraction ◽  
Volume Loss ◽  
Heart Rates ◽  
Patients With Heart Failure

Background Increases in heart rate are thought to result in incomplete left ventricular (LV) relaxation and elevated filling pressures in patients with heart failure with preserved ejection fraction (HFpEF). Experimental studies in isolated human myocardium have suggested that incomplete relaxation is a result of cellular Ca 2+ overload caused by increased myocardial Na + levels. We tested these heart rate paradigms in patients with HFpEF and referent controls without hypertension. Methods and Results In 22 fully sedated and instrumented patients (12 controls and 10 patients with HFpEF) in sinus rhythm with a preserved ejection fraction (≥50%) we assessed left‐sided filling pressures and volumes in sinus rhythm and with atrial pacing (95 beats per minute and 125 beats per minute) before atrial fibrillation ablation. Coronary sinus blood samples and flow measurements were also obtained. Seven women and 15 men were studied (aged 59±10 years, ejection fraction 61%±4%). Patients with HFpEF had a history of hypertension, dyspnea on exertion, concentric LV remodeling and a dilated left atrium, whereas controls did not. Pacing at 125 beats per minute lowered the mean LV end‐diastolic pressure in both groups (controls −4.3±4.1 mm Hg versus patients with HFpEF −8.5±6.0 mm Hg, P =0.08). Pacing also reduced LV end‐diastolic volumes. The volume loss was about twice as much in the HFpEF group (controls −15%±14% versus patients with HFpEF −32%±11%, P =0.009). Coronary venous [Ca 2+ ] increased after pacing at 125 beats per minute in patients with HFpEF but not in controls. [Na + ] did not change. Conclusions Higher resting heart rates are associated with lower filling pressures in patients with and without HFpEF. Incomplete relaxation and LV filling at high heart rates lead to a reduction in LV volumes that is more pronounced in patients with HFpEF and may be associated with myocardial Ca 2+ retention.

Heart Rate and Performance in Manual Missile Guidance

1971 ◽  
Vol 32 (2) ◽  
pp. 352-354
Author(s):  
Bengt Bergstroem ◽  
Peter Arnberg
Keyword(s):  
Heart Rate ◽  
Performance Data ◽  
Tracking Performance ◽  
Missile Guidance ◽  
Heart Rates ◽  
Laboratory Conditions ◽  
Stress Studies ◽  
And Performance

Earlier stress studies under laboratory conditions show that heart rates from 100 to 110 bpm are associated with significant decrements in missile-tracking performance. Data from real missile tracking by 8 operators with no stress deliberately induced indicate, however, that performance is unaffected up to 135 bpm, and only moderately affected in the 135- to 170-bpm region. The disagreement between the two sets of results highlights the difficulties in generalizing from stress experiments.

scholarly journals The Influence ofNrf2on Cardiac Responses to Environmental Stressors

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Reuben Howden ◽  
Eva Gougian ◽  
Marcus Lawrence ◽  
Samantha Cividanes ◽  
Wesley Gladwell ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Frequency ◽  
Low Frequency ◽  
Therapeutic Strategies ◽  
Environmental Stressors ◽  
Total Power ◽  
Airborne Pollutants ◽  
Cardiac Responses

Nrf2protects the lung from adverse responses to oxidants, including 100% oxygen (hyperoxia) and airborne pollutants like particulate matter (PM) exposure, but the role ofNrf2on heart rate (HR) and heart rate variability (HRV) responses is not known. We hypothesized that genetic disruption ofNrf2would exacerbate murine HR and HRV responses to severe hyperoxia or moderate PM exposures.Nrf2-/-andNrf2+/+mice were instrumented for continuous ECG recording to calculate HR and HRV (low frequency (LF), high frequency (HF), and total power (TP)). Mice were then either exposed to hyperoxia for up to 72 hrs or aspirated with ultrafine PM (UF-PM). Compared to respective controls, UF-PM induced significantly greater effects on HR (P<0.001) and HF HRV (P<0.001) inNrf2-/-mice compared toNrf2+/+mice.Nrf2-/-mice tolerated hyperoxia significantly less thanNrf2+/+mice (~22 hrs;P<0.001). Reductions in HR, LF, HF, and TP HRV were also significantly greater inNrf2-/-compared toNrf2+/+mice (P<0.01). Results demonstrate thatNrf2deletion increases susceptibility to change in HR and HRV responses to environmental stressors and suggest potential therapeutic strategies to prevent cardiovascular alterations.

Stress level in wild harbour porpoises (Phocoena phocoena) during satellite tagging measured by respiration, heart rate and cortisol

2009 ◽  
Vol 89 (5) ◽  
pp. 885-892 ◽  
Author(s):  
I.G. Eskesen ◽  
J. Teilmann ◽  
B.M. Geertsen ◽  
G. Desportes ◽  
F. Riget ◽  
...  
Keyword(s):  
Heart Rate ◽  
Respiration Rate ◽  
Serum Cortisol ◽  
Phocoena Phocoena ◽  
Heart Rates ◽  
Stress Effects ◽  
Respiration Rates ◽  
Stressed Animal ◽  
Cortisol Levels ◽  
Satellite Tagging

During satellite tagging of harbour porpoises (Phocoena phocoena), heart rate, respiration rate and cortisol value were measured to evaluate stress effects during handling and tagging. Respiration rates were obtained using video recordings, heart rates were recorded and serum cortisol levels were analysed from blood samples. Differences in heart rates, respiration rates and cortisol levels before and during the tagging events were investigated. An overall significant decrease of 31.5% in respiration rate was found during the tagging event period, while mature porpoises respired significantly more often than immature individuals. Though significant differences in heart rates were found for some individuals, no general significant change for all animals was detected. We found no correlation between cortisol concentration and either heart rate or respiration rate, nor did we find any relationships between cortisol and month of year, sex and body length. As high individual variations occurred in response to tagging of harbour porpoises, it is not possible to give general advice based on the factors investigated, on how to reduce stress during handling. However, pouring water over the animal and lowering it into the water seem to stabilize a stressed animal. Therefore, general precaution and individual judgement based on experience is essential when handling wild harbour porpoises.

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